Taoiseach Bertie Ahern will attend the European Council in Brussels today to discuss the accession of two new states to the European Union.
The EC is expected to debate a report on the union's capacity to integrate new members and individual applicant countries.
Leaders are to welcome Romania and Bulgaria to the EU as new members with effect from January 1st.
The accession of those two states will complete a wave of expansion that began in 2004 when the EU admitted 10 mostly ex-communist central and eastern European countries.
Minister for Foreign Affairs Dermot Ahern will also attend the council meeting.
The two-day Brussels summit comes after the 25-member bloc agreed on Monday to a partial freeze in Turkey's entry talks, a move that should help appease some of those who question the European credentials of the predominately Muslim country.
According to a draft final statement for the meeting, EU leaders will reaffirm a commitment eventually to admit Turkey, as well as the states of the western Balkans - Albania, Bosnia, Croatia, Macedonia, Montenegro and Serbia.
But they will call for stricter monitoring of candidates' progress to ensure tough issues such as judicial reform and fighting corruption are tackled early on.
Leaders will also make clear that before taking in any more countries, the European Union must reform its creaking institutions - a process Germany aims to revive when it takes over the rotating presidency from Finland next month.